138 lines
3.8 KiB
C
138 lines
3.8 KiB
C
/*
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* Copyright 2020 Piotr Caban for CodeWeavers
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
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*/
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#ifndef __WINE_BNUM_H
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#define __WINE_BNUM_H
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#define EXP_BITS 11
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#define MANT_BITS 53
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static const int p10s[] = { 1, 10, 100, 1000, 10000, 100000, 1000000, 10000000, 100000000 };
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#define LIMB_DIGITS 9 /* each DWORD stores up to 9 digits */
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#define LIMB_MAX 1000000000 /* 10^9 */
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#define BNUM_PREC64 128 /* data size needed to store 64-bit double */
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#define BNUM_PREC80 2048 /* data size needed to store 80-bit double */
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/* bnum represents real number with fixed decimal point */
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struct bnum {
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int b; /* least significant digit position */
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int e; /* most significant digit position + 1 */
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int size; /* data buffer size in DWORDS (power of 2) */
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DWORD data[1]; /* circular buffer, base 10 number */
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};
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static inline int bnum_idx(struct bnum *b, int idx)
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{
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return idx & (b->size - 1);
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}
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/* Returns TRUE if new most significant limb was added */
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static inline BOOL bnum_lshift(struct bnum *b, int shift)
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{
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DWORD rest = 0;
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ULONGLONG tmp;
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int i;
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/* The limbs number can change by up to 1 so shift <= 29 */
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assert(shift <= 29);
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for(i=b->b; i<b->e; i++) {
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tmp = ((ULONGLONG)b->data[bnum_idx(b, i)] << shift) + rest;
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rest = tmp / LIMB_MAX;
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b->data[bnum_idx(b, i)] = tmp % LIMB_MAX;
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if(i == b->b && !b->data[bnum_idx(b, i)])
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b->b++;
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}
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if(rest) {
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b->data[bnum_idx(b, b->e)] = rest;
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b->e++;
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if(bnum_idx(b, b->b) == bnum_idx(b, b->e)) {
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if(b->data[bnum_idx(b, b->b)]) b->data[bnum_idx(b, b->b+1)] |= 1;
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b->b++;
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}
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return TRUE;
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}
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return FALSE;
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}
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/* Returns TRUE if most significant limb was removed */
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static inline BOOL bnum_rshift(struct bnum *b, int shift)
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{
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DWORD tmp, rest = 0;
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BOOL ret = FALSE;
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int i;
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/* Compute LIMB_MAX << shift without accuracy loss */
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assert(shift <= 9);
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for(i=b->e-1; i>=b->b; i--) {
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tmp = b->data[bnum_idx(b, i)] & ((1<<shift)-1);
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b->data[bnum_idx(b, i)] = (b->data[bnum_idx(b, i)] >> shift) + rest;
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rest = (LIMB_MAX >> shift) * tmp;
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if(i==b->e-1 && !b->data[bnum_idx(b, i)]) {
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b->e--;
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ret = TRUE;
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}
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}
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if(rest) {
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if(bnum_idx(b, b->b-1) == bnum_idx(b, b->e)) {
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if(rest) b->data[bnum_idx(b, b->b)] |= 1;
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} else {
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b->b--;
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b->data[bnum_idx(b, b->b)] = rest;
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}
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}
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return ret;
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}
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static inline void bnum_mult(struct bnum *b, int mult)
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{
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DWORD rest = 0;
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ULONGLONG tmp;
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int i;
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assert(mult <= LIMB_MAX);
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for(i=b->b; i<b->e; i++) {
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tmp = ((ULONGLONG)b->data[bnum_idx(b, i)] * mult) + rest;
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rest = tmp / LIMB_MAX;
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b->data[bnum_idx(b, i)] = tmp % LIMB_MAX;
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if(i == b->b && !b->data[bnum_idx(b, i)])
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b->b++;
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}
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if(rest) {
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b->data[bnum_idx(b, b->e)] = rest;
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b->e++;
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if(bnum_idx(b, b->b) == bnum_idx(b, b->e)) {
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if(b->data[bnum_idx(b, b->b)]) b->data[bnum_idx(b, b->b+1)] |= 1;
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b->b++;
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}
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}
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}
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#endif /* __WINE_BNUM_H */
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